Motorized sliding support mechanisms are well-known and used to support structures whose position needs to change under different circumstances. An example is a motorized drawer. A more demanding example application is a “slide-out” module commonly included in a recreational vehicle (RV) or motor home. RVs will frequently include living spaces which can be expanded when the vehicle is parked to provide additional room. These “slide-outs” extend from the outer walls of the vehicle and are suspended over the ground. For convenience, and because slide-outs can be extremely heavy, it is often desirable to provide them with a motorized mechanism to automatically extend and retract the slide-out as desired. Some of these motorized mechanisms use a set of rack and pinions connected to the sides of the slide-out. Electric motors drive the pinions which engage with the rack and drive the slide-out forward or backward relative to the pinions which are typically mounted in an assembly which includes the motor and resides within a compartment within a side of the vehicle.
Conventional motor-driven sliding support mechanisms such as those used for RV slide-outs have deficiencies. For example, the rack and pinions may be prone to binding or degradation (e.g., abrasion and wear of teeth on the pinions and the corresponding grooves in the rack) which reduces the ability of the motor to slide the supported structure with the electrical power available. Some conventional mechanisms can result in poor gear mesh with the rack under common operating conditions. Additionally, some conventional mechanisms fail to solidly couple the motor to the shaft and other components, which can lead to severed motor wires when the mechanism experiences unexpected movements or forces. These and other problems may cause the motor to fail. Furthermore, the mechanisms coupling the motor to the pinions frequently make it difficult or impossible to move the mechanism manually in the event of a motor failure. In the example of an RV slide-out, these failures may occur in remote locations while also making it dangerous or impossible to drive the RV to a repair facility.